The initial purpose of this project was to examine abnormal pain perception and health care seeking behavior among persons with fibromyalgia (FM). Our initial subject groups consisted of 66 rheumatology clinic patients with FM, 39 community residents with FM who had not obtained medical care for their painful FM symmptoms in the past 10 years (i.e., nonpatients), and 39 healthy controls recruited from the community. We found that both patients and nonpatients with FM show significantly lower pain threshold levels and produce significantly higher scores on an index of sensory discrimination than healthy controls. These findings were replicated at 1- and 2-year followup assessments. These findings indicated that abnormal pain perception is associated with FM independently of health care seeking behavior. Moreover, it was found that lifetime history of psychiatric disorders was the best psycho-social predictor of obtaining health care at a tertiary care, rheumatology clinic for FM symptoms, i.e., greater psychiatric morbidity was associated with health care seeking. This indicated that the high levels of psychiatric morbidity seen in tertiary care clinic patients with FM is more strongly related to health care seeking than to the disorder itself. This project has been renewed by the NIH for another four years. The purpose of the second cycle of the project is to examine functional brain activity in three groups of subjects during resting conditions and during exposure to an acute painful stimuluus. These groups are 30 patients with fibromyalgia, 30 patients with chronic fatigue syndrome, and 30 healthy controls. Functional brain activity is assessed by single photon emission computed tomographic imaging. Four subject protocols have been completed at present. It is anticipated that patients with fibromyalgia will show inhibited funtional brain activity, relative to patients with chronic fatigue syndrome and controls, in the thalamus and caudate nucleus during resting conditions and during painful stimulation. However, it also is expected that the fibromyalgia patients, compared to the other subject groups, will show higher levels of functional brain activity in the anterior cingulate cortex during painful stimulation.